TY - JOUR
T1 - Multiple developmental roles for CRAC, a cytosolic regulator of adenylyl cyclase
AU - Wang, Bin
AU - Shaulsky, Gad
AU - Kuspa, Adam
N1 - Funding Information:
We thank Sijie Lu and Dale Hereld for many helpful suggestions during the course of this work. We thank Richard Gomer for helping us with the time-lapse video recording. The RNase protection assays were performed in the laboratory of William F. Loomis and we appreciate his support during the course of this work. This work was supported by a USPHS grant from the National Institutes of Health and by an Advanced Technology Program Grant from the State of Texas. A.K. is an American Cancer Society Junior Faculty Research Fellow and a Kinship Foundation Searle Scholar.
PY - 1999/4/1
Y1 - 1999/4/1
N2 - Receptor-mediated activation of adenylyl cyclase (ACA) in Dictyostelium requires CRAC protein. Upon translocation to the membrane, this pleckstrin homology (PH) domain protein stimulates ACA and thereby mediates developmental aggregation. CRAC may also have roles later in development since CRAC-null cells can respond to chemotactic signals and participate in developmental aggregation when admixed with wild-type cells, but they do not complete development within such chimeras. To test whether the role of CRAC in postaggregative development is related to the activation of ACA, chemotactic aggregation was bypassed in CRAC-null cells by activating the cAMP-dependent protein kinase (PKA). While such strains formed mounds, they did not complete fruiting body morphogenesis or form spores. Expression of CRAC in the prespore cells of these strains rescued sporulation and fruiting body formation. This later function of CRAC does not appear to require its PH domain since the C-terminal portion of the protein (CRAC-ΔPH) can substitute for full-length CRAC in promoting spore cell formation and morphogenesis. No detectable ACA activation was observed in any of the CRAC-null strains rescued by PKA activation and expression of CRAC-ΔPH. Finally, we found that the development of CRAC-null ACA-null double mutants could be rescued by the activation of PKA together with the expression of CRAC-ΔPH. Thus, there appears to be a required function for CRAC in postaggregative development that is independent of its previously described function in the ACA activation pathway.
AB - Receptor-mediated activation of adenylyl cyclase (ACA) in Dictyostelium requires CRAC protein. Upon translocation to the membrane, this pleckstrin homology (PH) domain protein stimulates ACA and thereby mediates developmental aggregation. CRAC may also have roles later in development since CRAC-null cells can respond to chemotactic signals and participate in developmental aggregation when admixed with wild-type cells, but they do not complete development within such chimeras. To test whether the role of CRAC in postaggregative development is related to the activation of ACA, chemotactic aggregation was bypassed in CRAC-null cells by activating the cAMP-dependent protein kinase (PKA). While such strains formed mounds, they did not complete fruiting body morphogenesis or form spores. Expression of CRAC in the prespore cells of these strains rescued sporulation and fruiting body formation. This later function of CRAC does not appear to require its PH domain since the C-terminal portion of the protein (CRAC-ΔPH) can substitute for full-length CRAC in promoting spore cell formation and morphogenesis. No detectable ACA activation was observed in any of the CRAC-null strains rescued by PKA activation and expression of CRAC-ΔPH. Finally, we found that the development of CRAC-null ACA-null double mutants could be rescued by the activation of PKA together with the expression of CRAC-ΔPH. Thus, there appears to be a required function for CRAC in postaggregative development that is independent of its previously described function in the ACA activation pathway.
KW - Cell differentiation
KW - Spore formation
KW - cAMP
KW - cAMP-dependent protein kinase
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U2 - 10.1006/dbio.1998.9193
DO - 10.1006/dbio.1998.9193
M3 - Article
C2 - 10075837
AN - SCOPUS:0033120141
SN - 0012-1606
VL - 208
SP - 1
EP - 13
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -